1. Field of the Invention
This invention relates to a stacked ceramic body that can be utilized as a piezoelectric device for a piezoelectric actuator, and a production method thereof.
2. Description of the Related Art
Piezoelectric devices comprising stacked ceramic bodies, fabricated by alternately stacking a plurality of dielectric layers and electrode layers for applying a voltage to the dielectric layers, are known. Among them, a stacked ceramic body the dielectric layer of which is formed of lead zirconate titanate (PZT) and the electrode of which is formed of copper has gained a wide application as a piezoelectric device because it is economical and is considerably free from the migration that has been observed in a silver-palladium electrode.
In the stacked ceramic body including the dielectric layers containing lead and the electrode layers containing copper, however, metallic lead is isolated from the dielectric layer during sintering of an unsintered stacked body in a production process of the stacked ceramic body, and this metallic lead and metallic copper of the electrode layer together form a liquid phase and flow out in some cases. Further, the electrode layer often aggregates and is interrupted due to the reaction between metallic lead isolated from the dielectric layer and metallic copper of the electrode layer (see later-appearing FIGS. 1(a) and 1(b)). Lead oxide contained in the dielectric layer forms a liquid phase with copper oxide, is diffused into the dielectric layer, and sometimes denatures the dielectric layer.